Convert text to a number — practice exercise

What you'll be asked to do

1. 1.Convert text to a numberexercise · easy · 10 min

   Convert the text and add eight to it.

   Passes when: #out should show 50.

2. 2.Convert a number to textexercise · easy · 10 min · practice plan

   Convert a number to a string and report its type.

   Passes when: #out should show string.

3. 3.Convert to a booleanexercise · easy · 10 min · practice plan

   Report what Boolean gives for an empty string.

   Passes when: #out should show empty is falsy.

4. 4.Handle a failed conversionexercise · easy · 10 min · practice plan

   Report a message when the text cannot become a number.

   Passes when: #out should show not a number.

5. 5.Add two form valuesexercise · medium · 10 min · practice plan

   Convert both inputs before adding them.

   Passes when: #out should show 25.

6. 6.Fix the values joined instead of addedbug fix · easy · 8 min

   Text values join with plus rather than adding.

   Passes when: #out should show 25.

7. 7.Fix the conversion applied too latebug fix · easy · 8 min · practice plan

   The join has already happened before the conversion.

   Passes when: #out should show 50.

8. 8.Fix the failed conversion uncheckedbug fix · easy · 8 min · practice plan

   A failed conversion gives NaN, which must be checked for.

   Passes when: #out should show not a number.

9. 9.Fix toString called on nullbug fix · easy · 8 min · practice plan

   String works on null, but toString throws.

   Passes when: #out should show null.

10. 10.Fix the empty string assumed to be NaNbug fix · easy · 8 min · practice plan

    Number of an empty string is 0, not NaN.

    Passes when: #out should show zero.

Between them these tasks cover Number, String and Boolean.

Looking for a different chapter? See every practice set, or switch to the interview theory questions.